The present invention relates to the field of wireless communications generally, and more specifically to radio frequency (RF) boosters for wireless communications.
The personal stations of wireless cellular phones are divided into several classes according to the level of RF power they transmit. An RF booster may be included in the xe2x80x9chands-freexe2x80x9d communications kit of an automobile to improve wireless communications when a handset (personal station) is placed in holder of the hands-free kit. The RF booster increases the transmitted power of the combination xe2x80x9cboosterxe2x80x94personal stationxe2x80x9d above the transmitted power of the personal station itself. The power transmitted by the combination must still remain within defined limits corresponding to a class. This function is performed by the system power control.
An improved power control is desired.
The present invention is a power level determination device which provides an output voltage usable as a specific reference power level corresponding to each RF input power level.
The device includes a peak detector, which detects a pulse-type signal at its input and provides a non-pulse-type signal at its output.
N comparators are provided, where N is an integer. Each of the N comparators has an output, a first input coupled to the output of the peak detector, and a second input coupled to a respectively different threshold voltage.
N exclusive-OR components are provided. A first one of the N exclusive-OR components is coupled to the output of a first one of the N comparators. Each of the remaining Nxe2x88x921 exclusive-OR components is coupled to the outputs of a respectively different pair of the N comparators, so that at any given time, a single one of the N exclusive-OR components has an output signal of a logic level that is different from the logic level of the outputs of the remaining Nxe2x88x921 exclusive-OR components.
N circuits are coupled to respective ones of the N exclusive-OR components. Each of the N circuits provides a respectively different predetermined output voltage if the exclusive-OR component to which that circuit is coupled is the single one of the N exclusive-OR components, as an indication of a power level of the pulse-type signal.